Respect for good laws is a good thing.
There are police officers in every country who have decent values and genuinely try to do an honest job. But even those decent people, with few exceptions, will do whatever they can to cover up crimes by their buddies. And for some reason, we all go along with it.
An example. What is the difference between serial rapists who gets 85 years, or 327 years, or 428 years, or 764 years and one who gets 10 years? The serial rapist who got 10 years was carrying a badge. At every step he was protected, until publicity got to be too much.
Is that disparity unusual? Do a Google search of the phrase "police officer sentenced" or "police chief sentenced" (in quotes) and judge for yourself. There are exceptions of course. A policeman in my town who raped a number of women was sentenced to 80+ years. But only after his crimes were ignored and minimized by his fellow officers for years.
Who do police work for?
There is an old Abbott and Costello episode where Costello walks up to a policeman and says "Are you a public servant?" The policeman says "Sure I am". So Costello says "Get me a glass of water". The conversation goes back and forth. Ultimately Costello lays down the law and schools the policeman on where his authority comes from.
Every group has bad apples, but why do police, more than any other group, refuse to clean their own ranks?
Imagine you are an attractive young woman. A police officer asks you out on a date. You don't care for him, so you say no. He asks you again, again you say no.
Next, he pulls up to you while he is in uniform and informs you that you are under arrest. Maybe you are scared but you think that once you are at the police station you will be safe. Eventually he is caught, but even then there was a lot of resistance to arresting him or convicting him of a crime. The details of the case are on the internet if you want to research it.
Any abduction followed by a rape and murder would normally make headlines in a large area. This case did not. In fact it was largely ignored, except by activist sites. Local news sites had a minimum of questions about numerous disturbing signs that police were tolerating or ignoring their own misconduct.
It's worth noting that there is still very little about this case in the media. Notice the reference at http://behindthebluewall.blogspot.com/2005/05/ak-sonya-dora-nitcuk-ivanoffmurdered.html.
Also worth noting that this scenario (minus the murder, usually) happens more often than most people would guess. Here is another example, from June 2012. The common denominators are usually a) a low status woman and b) very little public interest in the case. Why is it a trivial matter when a police officer commits a rape? Read the article carefully.
Does this ever become a mainstream issue?
Recently there were three high profile corruption cases involving the New York Police Department. According to the New York Times "All these cases involved New York City police officers and unfolded or were resolved in recent months. But beyond the fact of criminal charges against those sworn to protect the public, they all had another thing in common: Each case was uncovered by an outside agency, not the Internal Affairs Bureau of the New York Police Department, the unit responsible for unearthing and investigating officers’ wrongdoing."
So the begged question is, would these cases have ever been uncovered by the internal affairs office of that police department, if outside agencies had not done that work? The most likely answer is no. One of the cases involved ticket fixing, which has gone on in the open in NYC for decades, literally. It's not even a secret.
Even in a country as civilized as England, out of over 8,500 allegations of misconduct against individual police, only 13 convictions resulted.
One phenomenon in almost all countries is the prevalence of police involvement in sex crimes.
A uniform and badge and gun, and the forced respect they involve, appeal to the sort of person who associates sex and violence. Perhaps for that reason, police commit sex crimes at a far higher rate than normal citizens. Of course in less developed countries, with less media coverage, less education, etc, the problem is far worse. In many countries, rape by police is a routine matter and completely ignored unless someone forces it into the news.
In both the third world and America, there is virtually no accountability unless there is publicity, and police are so focused on "sticking together" that there is almost never publicity.
Most policemen do consider themselves honest. Unfortunately, their belief in their own integrity usually comes from their uniform. The idea being "I am wearing a uniform and carrying a badge, and therefore what I do is right".That isn't to say police are worse than regular citizens, in most cases they are not. It's simply that citizens are aggressively pursued when they break the law. Policemen are not, as a general rule.
Are most police in America fairly honest?
Of course. So are most cab drivers, most bakers, most engineers etc. In fact even most criminals are honest 99% of the time. The difference between police and these other groups is that police seldom are held accountable for their misconduct, unless there is publicity that forces action. The very rare Serpico who appears from time to time, the true enforcer of laws without respect for office, is nowadays almost unheard of.